Nasal mask



FIG. 1 is a front top and left perspective view of a nasal mask showingmy new design;

FIG. 2 is a front view thereof;

FIG. 3 is a left side view thereof, with the right side view thereofbeing a mirror image thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a bottom view thereof; and,

FIG. 6 is a top view thereof.

The ornamental design for a nasal mask, as shown and described.